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Oil resistant o-rings on the basis of acrylonitrile butadiene rubber (NBR) reinforced by nanoclay were produced via a traditional industrial method in accordance with aviation standard, AMS 7272. The production of nanocomposites comprised the compounding of nanocomposite with optimum mechanical properties and minimum contents of used carbon black and nanoclay, design and manufacturing of the required mold and finally compression molding of the oring. Mechanical and morphological properties of NBR/nanoclay compounds were optimized by introduction of proper contents of a compatibilizer containing a mixture of resorcinol and hexamethylene tetramine through using a master batch production method. The prepared nanocomposites were characterized using X-ray diffraction (XRD) analysis, curing measurements and tensile test analysis. The XRD analysis showed that the compatibilizer facilitates the intercalation of nanoclay silicate layers with the rubber chains which leads to the increase of their basal spacing. The cure characteristics of the nanocomposites showed a decrease of scorch time and increase the cure rate index with the nanoclay loadings. Furthermore, the minimum scorch time and maximum cure rate index could be achieved through using the appropriate content of compatibilizer. The results exhibit that the nanocomposites containing the compatibilizer have higher mechanical properties especially at higher deformations compared to the corresponding uncompatibilized nanocomposites

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The overarching goal of this research is to use polymeric composites enriched with diatomic soil to improve petroleum-contaminated clayey soil. The effect of petroleum on the geotechnical properties of clayey soil was investigated in the laboratory in the first stage using uniaxial, direct shear, and permeability tests. The polymeric composite material was then created and mixed with the diatomic soil. The geotechnical properties of petroleum-contaminated clayey soil were studied using a polymeric composite material mixed with diatomic soil (PCD). Petroleum reduced the shear resistance, internal friction angle, and uniaxial resistance of the clay for contamination percentages ranging from 0% to 12%. Whereas 12 percent petroleum content causes the greatest changes in soil mechanical resistance. According to the results of the direct shear test, adding 5.5 percent PCD increases the shear resistance of the base material and contaminated base material to average values of 32 and 48 percent, respectively. Furthermore, the results of the petroleum permeability test show that adding 5.5 percent PCD reduces soil permeability. The results show that the improved clay by PCD can be used as a liner for the base of petroleum reservoirs.

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In recent years, with the advancement of nanoscience, many scientists have used nano materials to solve existing problems in various sectors of oil industry. Nanofluids made with these materials can facilitate the separation of oil and gas in a reservoir and increase oil recovery factor compared to current methods. Therefore, in this work, the effect of clay nanoparticles on oil recovery factor was investigated. For this purpose, two different base fluids, water and ethanol, were used to disperse the nanoparticles. The effect of adding clay nanoparticles on viscosity changes and interfacial surface tension was determined. Also, in order to investigate the effect of nanoparticle concentration in the base fluid on the ultimate oil recovery factor, nanofluids with 3 and 5 wt% were prepared. Results show that oil recovery factor increases significantly in these conditions by adding them into the base fluid, though nanofluids included clay nanoparticles have less stability. Also, the effect of these nanoparticles dispersed in water is greater than in ethanol. For example, at 5 wt%, oil recovery factor for water based nanofluid was 49.7% and for ethanol based nanofluid was 46%.

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The properties of soils affected by salinity and the processes involving degradation of soil structure are relatively well-known. However, the effects of saline and sodic condi-tions on the physical and mechanical properties of soils have been studied to a lesser ex-tent. In this research, the effects of electrical conductivity (EC) and sodium adsorption ra-tio (SAR) of solutions were assessed on soils containing various amounts of organic matter under laboratory conditions. The soils used were collected from the Dasht-e-Naz of Sari region in the north of Iran and contained the same clay type, predominantly Illite. The major difference between the soils was their organic matter content. The treatments con-sisted of applying solutions with definite EC and SAR (two levels of EC: 0.5 and 4 dS/m and three levels of SAR: 0, 5 and 15). With an increase of SAR, the wet aggregate stability (WAS) decreased and the amount of dispersible clay (DC) increased. At a similar SAR, higher EC values were associated with lower DC. The order of average aggregate stability of soils were: virgin soils > soils under continuous cultivation of Festuca > soils under in-tensive cultivation with regular crop rotation > soils under continuous cultivation of Ag-ropyron. The analysis of variance showed significant differences (at 1%) between soil types, soil sampling depths, EC and SAR.

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Research subject:Well-designed plastic foams, with respect to their cell density and cell size, open-or-close cells, and the cell uniformity, compared to their counterpart unfoamed plastic parts, beside of having the advantages of less material consumption, dimensional stability, better processability, and a higher surface quality, they can have superior mechanical and physical properties, including strength to weight, impact strength, thermal and dielectric properties. The temperature distribution in the different zones of the extruder, the qualities and quantities of the nanoparticle additives and their dispersion in the polymer matrix can have significant effect on the mechanical properties of the produced foams by the extruder.
Research approach: In this study, using an extruder, MA-g-polypropylene microcellular foams, containing 3, 7 and 9 wt% of nano-clay particles, were produced under three temperature arrangements on the extruder and the material and the processing effects on the mechanical properties were investigated.  
Main results: The result of this investigation shows that adding of nanoclay improves the mechanical properties of MA-g-PP.s foams. As an example, the results show that the sample with 7 wt% of surface modified nanoclay, owns about 10% higher impact toughness compared to the samples produced without nanoclay. Also for the same samples a rise of about 5% was recorded in Young's modulus. The microstructural studies of the produced foams by scanning electron microscope (SEM) show that adding of nanoclay can result on more foam uniformity and smaller cell size. In this study, the smallest average cell size (87.5 μm) and the lowest density (0.3 g/cm³) were recorded for a sample with 7wt% nanoclay.

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In the first season of archeological excavations of Tepe Zarnagh in 2013, many clay figurines of human and animal forms were discovered, which belonged to the Early Bronze Age. Contrary to most of the figurines found around the world, which are feminine fertility goddesses; Tepe Zarnaghs’figurines are male forms. Significant number of this type of male figurines reveals the special social structure of the respective society and the special religious status of this type of figurines in that society. As most of the archeological studies in sites related to Kura-Araxs culture have focused on the architectures and potteries, no research has been done on the clay figurines. Hence, by studying Kura-Araxs figurines, in this paper we attempt to analyze and categorize statuettes of Tepe Zarnagh and identify the relationship between these artifacts and social and ideological factors and social structure of Kura-Araxs region in Early Bronze Age.      

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Soils of the arid–semiarid Karaj Basin in north-central Iran have formed on alluvium-colluvium derived from mixed calcareous-gypsiferous marls of Miocene and basic igneous rocks of Holocene age. In order to characterize and classify the soils and to determine the soil-landscape relationship in the area, sixteen pedons located on different physiographic positions have been described, sampled and analysed. According to field descriptions these soils all show evidences of carbonate accumulation to be classified as Calcids or Cambids. However, soils with well developed argillic and calcic horizons have been ob-served on apparently younger colluvial fans, whereas the less developed soils with calcic and cambic horizons occur on older upper alluvial plains. Due to the calcareous gravelly soil parent materials, clay films are mainly masked by carbonates and their identification in the field is mostly impossible. Also due to the adherence of these clay films to coarse gravels and their separation from the fine earth materials through sieving, they may not sometimes appear on the particle size distribution analysis. Yet under the microscope the soils show enough indicators to be characterized as argillic horizon and to classify the soils properly according to Soil Taxonomy as Argids instead of Calcids. Also, these find-ings point out the relatively older ages of these physiographic surfaces now they are cov-ered by younger colluvial materials.

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Considerable information exists in the literature showing that expansive layer silicates are not the only clay minerals present in vertisols. However, the presence of a very high clay content dominated by fine clay, regardless of the clay type, together with the wetting and drying cycle in the soil can also produce a high shrink-swell potential. We studied some vertisols with diverse parent materials and climates from western Iran to investigate the role of parent material and climate on formation of these soils. The vertisols of Fars Province (Southwest Iran) have formed on calcareous sediments with ustic-hyperthermic soil moisture and temperature regimes and a mineralogical composition dominated by a palygorskite-chlorite suite. The vertisols of Lorestan Province (Midwest Iran) are also formed from calcareous sediments under the xeric moisture and thermic temperature re-gime, and contain vermiculite as the dominant clay mineral. In Kermanshah Province, vertisols have formed on limestone or in calcareous sediments. They have xeric-thermic soil moisture and temperature regimes. In Ardebil Province, vertisols are formed on vol-canic sediments, and they have xeric-mesic soil moisture and temperature regimes. All vertisols, except those from Fars Province, are classical ones and include montmorillonite in the clay fraction. Our study shows that the interparticle pore size that is controlled by the size of primary particles, regardless of its nature, contributes to the shrink-swell po-tential in the soils we studied in Iran.

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Abstract In general, methods of lightweight aggregate concrete mix design are not much different with the ordinary concrete mix designs, except that in LWAC, volumetric method must be used for determining the amount of aggregates (normal and lightweight). In some countries, the same mix design of conventional concrete (normal weight) is also used for this purpose. Due to the specific restrictions of these methods, it is difficult to use them in certain cases where concrete slump is specified, or high strength concrete is needed. In this paper, a new method for the mix design of lightweight aggregate concrete has been proposed using a type of artificial lightweight aggregate (expanded clay, Leca). This approach is based on two-phased model (particle and matrix), and has better performance compared to other methods, due to the possibility of considering the properties of cement paste and particle in terms of access to consistency (slump) and the required strength of the concrete made. Also in this method, the percentage composition of normal and lightweight aggregates is chosen to achieve minimum space (porosity), so, the minimum amount of cement paste will be used to achieve the above requirements, and the economic saving.

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Abstract: Marun dam with a height of 170m is one of the largest embankment dams in Iran. The dam is a zoned rockfill dam with a central clay core. Due to the importance of safety and stability control of the dam body, a complete monitoring network including different instrumentation systems, has been designed and installed in the dam body. In this paper, the data obtained from the instruments, installed in the clay core, were processed and interpreted. Based on the outcomes, the behavior of the dam body during the construction in the impounding stage and operation period was evaluated and discussed. This study consists of three major parts including: the pore pressure distributions, stress states conditions in the clay core and evaluation of its settlements and deformations in the dam body.

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The present study was carried out in Kharkeh Research Station, Kurdestan Province, western Iran to investigate the effects of the change in land use on the degradation of Mol-lisols, their organic carbon content, clay mineralogy and K+ status. The study area was partly under cultivation (for over 40 years) and partly preserved as rangelands. The re-sults revealed that Mollisols are the dominant soils in non-cultivated natural rangelands. The adjacent cultivated soils, however, lack enough organic carbon to meet the require-ments of Mollisols. Cultivation practices had exerted adverse effects on some such major soil properties as organic carbon, cation exchange capacity, as well as macro- and micro-structure. Clay minerals and different forms of potassium did not show significant differ-ences in the two land uses. Parent material rich in such potassium bearing minerals as feldspars and mica, as well as the dominance of illite in soils, were probably the main fac-tors responsible for adjustment of the soil K+, rendering the changes relatively non-significant.

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The purpose of this paper is the study of tensile and bending behavior of polyamide with nano clay by different modifier and corrections in the work condition. Many previous studies about behavior mechanical had been done in standardize condition or after dried samples. However result of this research is not proper for applied design. In this research polyamide is mixed with three kinds of nano clay, By the way of melt intercalated with 9, 7, 5, 3, 1 percents. The samples were tested by X-ray diffraction, for clarifying nano composite morphology. After that tensile and bending tests were done on standard samples. Results show that mechanical property can be improved by added any kind of nano clay to polyamide. Nanocomposites have exfoliated structure if nano clay had more compatibility to polyamide. Moduli tensile and bending were improved with increase nano clay concentration. Although CL30B have best exfoliated structure therefore has most modules in beading and tensile.

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Abstract: Dyes and pigments are the major and important groups of chemical compounds with high amount of production and consumption amongst various environmental pollutants. For example, the annual imported amount of dye is over 7000 tons in Iran. Most of the dyes used in textile industries are considered either as inert or non-toxic, although some are not totally innocuous. The important fact is that most of them are made of carcinogenic chemicals that may be reformed as a result of metabolism. More than 50 percent of dyes consumed in different processes are discharged to wastewater, which in addition to changing the color of water, are preventing light penetration into the water and photosynthetic function that leads to destruction of aquatic ecosystem and some aquatic species. In recent years, increasing production and use of synthetic dyes, which have more complex structure and chemical stability as compared to natural dyes, more attention has been paid to their environmental pollution and importance of their treatment. Biological treatment is often the most economical alternative as compared to the physical and chemical treatment processes. But as most of dyes are hardly biodegradable, biological systems donot have capabilities in their removal. In expensive chemical processes, unexpected by- products and sludge are the main disadvantages. So, application of physical methods is preferred to control these kinds of pollutions. Different physical methods are also widely used, such as membrane–filtration processes and adsorption techniques. Adsorption is one of the most popular, flexible and effective methods that provides an attractive alternative for the treatment of colored water, especially if the sorbent is inexpensive and does not require an additional pre-treatment step before its application. It also does not result in the formation of harmful substances. Based on the aforementioned reasons, two adsorbents of sawdust and bentonite clay (absorbent aluminium phyllosilicate) were applied for the removal of cationic astrazon blue (F2RL) dye from wastewater regarding the two main factors of cost and availability in Iran, especially in the central provinces of the country. The parameters of pH, dye concentration and contact time were studied in this research. According to the study results, the optimum pH of 7 was found for the removal of dye for both sawdust and bentonite. Data analysis showed that increasing of the initial dye concentration resulted in the decreasing of removal efficiency. The maximum efficiency for the removal of dye from the solutions with the initial concentration of 25, 50 & 100 mg/L was 96.75, 91.11 & 79.26 percent for sawdust and 97.32, 96.78 & 94.62 percent for bentonite, respectively. The equilibrium time was 240 and 90 minutes for sawdust and bentonite, respectively. For the effect of adsorbent dosage on the removal of dye, experiments were carried out with two initial dye concentrations of 50 & 100 mg/L. By increasing of the adsorbent dosage, the maximum efficiency for the removal of dye from the solutions with the initial concentration of 50 and 100 mg/L increased from 53.46 to 97.06 percent and 49.76 to 96.83 percent, respectively, for sawdust, and from 90.78 to 99.64 and 86.44 to 99.46 percent, respectively, for bentonite clay. Analysis and calculation of separation factor (RL) of the result showed that adsorption of dye by sawdust and bentonite corresponds with Langmuir isotherm.

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In this paper, the influence of nanoclay Closite 30B on ballistic impact behavior of 2D woven E- Glass/Epoxy laminated composite has been investigated experimentally. The glass/epoxy/nanoclay laminate nanocomposites have 12 layers and 60% fiber volume fraction is manufactured by VRTM method. Fibers have a plain weave configuration with density of 200gr/m2, while The epoxy resin system is made of a diglycidyl ether of bisphenol A (DGEBA), Epon 828, as the epoxy prepolymer and a polyoxypropylene diamine with average molecular weight of 400 gr/mol, Jeffamine D-400, as the curing agent. The nanoclay Closite 30B is dispersed into the epoxy system in a 0%, 1%, 2%, 3%, 5% and 7% ratio in weight with respect to the matrix. Morphological studies using XRD revealed that nanostructures are mostly in intercalated form rather than exfoliated form. In additional to tensile test, ballistic impact test is carried out on the samples by flat-ended projectile with 14gr mass and 9.77mm diameter in 130m/s, 142m/s and 155m/s velocities. The results have shown that not only the mechanical properties, but also ballistic impact resistance can be improved with adding nanoclay.

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The potassium pools of five major physiographic units of Urmia region in Western Azarbaijan Province were studied to investigate the distribution of K forms as a function of clay mineralogy and physiographic units. For this, soil samples from different horizons of ten pedons were selected and analyzed for physiochemical properties, mineralogy of clay fraction, and forms of K. Analyses of XRD revealed that the soils are similar in their clay mineralogy, consisting of illite, smectite, chlorite, and kaolinite, but with different in contents. Illite was higher in the Piedmont Plains (PP) followed by Plateaux (Pl), River Alluvial Plains (RAP), Colluvial Alluvial Plains (CAP), and Lowlands (LL) units, whereas a higher content of smectite was observed available in the Pl followed by PP, LL, RAP, and CAP units. Several such simultaneous processes as mineral weathering and soil forming, biocycling processes, and geomorphologic conditions had resulted in significant difference in K forms in the soils studied. A wide variation in total K (HF-extractable K) (0.54-1.1%), non-exchangeable K (280-450 mg kg-1), and exchangeable K (217-330 mg kg-1) were recorded among different physiographic units. Statistically significant differences (P≤ 0.05) were observed in the levels of mineral K, HNO3-extractable K, and non-exchangeable K in soils of high illite (30-50%) as compared with those of low illite contents (10-30%). A highly significant positive relationship was recorded between total K and illite content (r2= 0.85, P 0.001) and as well between non-exchangeable K and illite contents (r2= 0.84, P 0.001) suggesting that these pools of K are mainly released from the frayed edges and wedge zones of illite. The soils were categorized into two major groups based on the physiographic unit's assertion and soil solution K content: first group comprised of Pl and PP units while the second group of RAP, CAP, and LL units.

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Due to disadvantages of synthetic packaging materials such as migration into food, polluting of environment, difficulty of recovery, high costs of raw materials and production, also for development of properties of starch based edible film, in this study nanocomposite films from starch and montmorillonite (MMT)  fabricated and their properties investigated. In this regard, nanocomposite films formulated by mixing starch and four levels of nanoclay (0, 1, 3 and 5%) and three different concentrations of glycerol (20, 30 and 40%), then the physical and mechanical properties of film measured and appropriate film selected.  5 % nano-clay could  improve tension resistance (38%) and moisture permeability (33%). The results from XRD showed that nanoclays spread evenly in starch polymer. The effects of ultrasound waves on the optimum film were investigated. These waves improve mechanical properties and permeability of films remarkably. 30 minutes was the best time of ultrasounication processing. Results showed that optimum nanocomposite of starch-nanoclay could be used as a biodegradable suitable packaging for preserving food.

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The objective of this work was to investigate the effect of nanocaly on fatigue life of air spring. The studies on the air spring fatigue life have shown that the inner layer of the rubber composite bellows of the air spring plays the most important role on its fatigue life. So, as a new idea to improve the life of the air spring, in this research, NR/BR and 0, 3, 5, 7 % of nanoclay were separately melt-blended. X-ray diffraction was employed to characterize the nanocomposite morphology. Then, the curing time of the unvulcanized compound was defined by rheometer test and the final nanocomposites compounds were provided according to their curing characteristics. After that, tensile, heat built-up, tear and fatigue tests were performed on the standard test specimens. It was shown that by increasing the nanoclay percentage, the elasticity modulus, tear strength and heat built-up were increased whereas tensile strength and elongation at break point were decreased. The results also showed that by the addition of 3 % and 5 % of nanocaly to NR/BR, its fatigue life was increased about 33 % and 57 %, respectively, whereas the fatigue life of the compound containing 7 % nanoclay was decreased about 14 %.

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In this paper, the influence of nanoclay Closite 30B on ballistic impact behavior of 2D woven E- Glass/Epoxy laminated composite has been investigated experimentally. The glass/epoxy/nanoclay hybrid laminate nanocomposites are manufactured by layup method under pressure. The nanoclay particles are Closite 30B and are dispersed into the epoxy system in a 0%, 3%, 5%, 7% and 7% ratio in weight with respect to the matrix. In additional to tensile test, ballistic impact test is carried out on the samples by flat-ended projectile with 8.9gr mass and 10mm diameter in 134m/s and 169m/s velocities. The results have shown that not only the mechanical properties, but also ballistic impact resistance can be improved with adding nanoclay.

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Recently, the study of nano materials in different fields of engineering science has been widely performed. In fact, the study on the behaviour of mixtures of nano material with other materials is among the new horizons in engineering research works. In this paper the impact of nanoclay on consolidation behaviour of bentonite in the presence of heavy metal contaminant is investigated. For this purpose, different percentages of nanoclay were mixed with bentonite and were additionally mixed with different concentrations of copper nitrate. Then, the odometer experiments performed on these prepared homogeneous samples in order to study the consolidation and permeability variations of samples. The results of this study show that the presence of industrial nanoclay causes an increase on the osmotic settlement of samples at the heavy metal concentrations up to 30 cmol/kg-soil of copper nitrate in comparison to the settlement of bentonite. Furthermore, the addition of industrial nano-clay to bentonite causes an increase in permeability of sample in comparison to the permeability of bentonite. This difference is more noticeable at high concentration of heavy metal. In addition, with an increase in external pressure, the permeability of bentonite sample and mixtures of bentonite/nanoclay gets closer to each others. This behaviour has been attributed to the presence of clay particles with nano dimensions in the mixtures of nanoclay-bentonite, the cation exchange capacity (CEC) and specific surface area (SSA) variations of samples due to the presence of nanoclay. In other words, according to the results of this study in the process of settlement of mixtures of bentonite and nano clay in the presence and absence of heavy metals the cation exchange capacity and specific surface area have the significant role. In this regard at the low concentration of heavy metals at the effective stress less than 100 kPa, cation exchange capacity governs the soil behaviour. However, at the effective stress more than 100 kPa, specific surface area is the governing factor which controls soil consolidation performance. Once the concentration of heavy metal increases in which it overcomes the soil buffering capacity, the heavy metals will neutralize negative charge of clay particles. Therefore, the cation exchange capacity of soil will have low effect on the settlement behaviour of soil. In such a case the specific surface area governs soil settlement process. For this reason due to the larger surface area of nano clays, the possibility for the secondary consolidation of soil increases.